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Simulation of radar sounder echo from lunar surface and subsurface structure

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Science China Earth Sciences 2010年第7期53卷 1043-1055页

作者： wenzhe fa YaQiu Jin Fudan Univ Key Lab Wave Scattering & Remote Sensing Informat MOE Shanghai 200433 Peoples R China

Space-borne high frequency (HF) radar sounder is an effective tool for investigation of lunar subsurface structure in lunar exploration. The primary strategy of radar sounder technology for subsurface structure detection is utilization of the nadir echoes time delay and intensity difference from the lunar surface and subsurface. It is important to fully understand electromagnetic wave propagation, scattering, and attenuation through the lunar media in order to retrieve information of lunar layering structure from weak nadir echoes of the subsurface, which is simultaneously interfered by strong off-nadir surface clutters. Based on the Kirchhoff approximation (KA) of rough surface scattering and the ray tracing of geometric optics, a numerical simulation of radar echoes from lunar layering structures is developed. According to the lunar surface feature, the topography of mare and highland surfaces is numerically generated, and the triangulated network is employed to make digital elevations of the whole lunar surface. Scattering from the lunar surface and subsurface is numerically calculated using KA approach. Radar echoes and its range images are numerically simulated, and their dependence on the parameters of lunar layering interfaces is discussed. The approach of this paper can also be utilized to investigate subsurface structures in Mars and other planetary exploration.

关键词： radar sounder lunar layering structure echo simulation and image

The modeling analysis of microwave emission from stratified media of non-uniform lunar cratered terrain surface for Chinese Chang-E1 observation

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Chinese Science Bulletin 2011年第11期56卷 1165-1171页

作者： JIN YaQiu fa wenzhe Key Laboratory of Wave Scattering and Remote Sensing Information (MOE) Fudan University Shanghai 200433 China

In China's first lunar exploration project,Chang-E 1,the multi-channel (3.0,7.8,19.35,37 GHz) microwave radiometers were aboard the satellite,with the purpose of measuring microwave brightness temperature from lunar surface and surveying the global distribution of lunar regolith layer thickness,and global evaluation of 3He *** analyze the modeling of microwave radiative transfer from three-layered media of lunar surface,some factors,such as the cratered lunar surface roughness,scattering of regolith particulate medium with temperature profile,are *** on the statistics of the lunar cratered terrain and using Monte Carlo (MC) method,the cratered lunar surfaces are numerically *** triangulated network is utilized to divide the undulated lunar surface into discrete triangle meshes with the size 10 m as a digital surface *** reflectivities of each plane mesh are calculated,and the average reflectivity for all MC-realized lunar surfaces is *** is found that under the spatial resolution of 30 km×30 km of Chang-E 1 radiometer observation,the lunar surface can be well modeled as a flat *** makes the predominance of the parameters,such as the regolith layer thickness and stratified structures,to be *** the radiative transfer equation of stratified media with dense scatterers,the scattering coefficient of the regolith particulate medium is found negligible,and the emission is mainly governed by the absorptive property of the *** temperature of multi-layered media,*** soil,regolith layer with temperature profile and underlying rock media,are derived and calculated,and relevant main factors to affect the modeling and emission simulation are analyzed.

关键词：月球探测工程微波发射分层介质地形表面陨石坑模型分析中国非均匀

Global inventory of Helium-3 in lunar regoliths estimated by a multi-channel microwave radiometer on the Chang-E 1 lunar satellite

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Chinese Science Bulletin 2010年第35期55卷 4005-4009页

作者： fa wenzhe JIN YaQiu Key Laboratory of Wave Scattering and Remote Sensing Information (MOE) Fudan University Shanghai 200433 China Institut de Physique du Globe de Paris Saint Maur des Fosses 94100 France

Helium-3(3He) implanted by solar wind in the lunar regolith is a valuable resource because of its potential as a fusion *** the basis of the Apollo regolith samples,a linear relationship between 3He abundance and solar wind flux,optical maturity and TiO2 content has been *** successfully launched its first lunar exploration satellite Chang-E 1(CE-1) on October 24,2007.A multi-channeled microwave radiometer was aboard the satellite with the purpose of measuring microwave thermal emission from the lunar surface *** the multi-channel brightness temperature(Tb) observed by CE-1,the global distribution of the regolith thickness was inverted from the multi-channel Tb,and was used to evaluate the total amount of 3He per unit area in the lunar *** global inventory of 3He was estimated as being 6.6×108 kg;3.7×108 kg for the lunar nearside and 2.9×108 kg for the lunar farside.

关键词：微波辐射计月球卫星氦-3 库存估计多通道月球探测卫星聚变燃料

SHARAD study on the structures and permittivity of a buried impact crater in Martian Central Elysium Planitia

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Science China Earth Sciences 2023年第11期66卷 2452-2462页

作者： Peng faNG wenzhe fa Jinhai ZHANG Yangting LIN Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Engineering Laboratory for Deep Resources Equipment and Technology Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100029China Institute of Remote Sensing and Geographical Information System School of Earth and Space SciencesPeking UniversityBeijing 100871China

The Elysium Planitia,located in the transition zone between the northern and southern hemispheres,is one of the key areas for studying the stratigraphic structure and geological history of *** studies have shown that this plain has undergone complex surface modification processes including fluvial and volcanic processes,and systematic progress has been made in the study of macro-geological ***,there are relatively few studies on the regional structure of the plain,which restricts our understanding of the regional geological processes.A buried impact crater in the central part of the Elysium Planitia could have recorded the surface modification process since the formation of the impact crater,however,it is difficult to distinguish the subsurface stratigraphy due to the weak orbital radar reflection *** this study,we denoised Shallow Radar data and obtained a radargram with clear subsurface *** estimated the permittivity of subsurface materials via a multilayer reflection *** results show that two subsurface reflectors divide the structure of the buried impact crater into three layers(overlying layer,underlying layer,and bottom layer).The shallow subsurface reflector covers almost the whole impact crater,while the deep subsurface reflector covers only the southwest part of the impact *** the permittivity inversion results with the geological background of lava activity in the Elysium Planitia area,we argue that the overlying layer may be a mixture of regolith and lava flow with low density,while the underlying layer and bottom layer are dense lava *** reflector between the underlying layer and bottom layer is probably a thin deposit derived from weathering between two lava activities,and its possible formation mechanism is as follows:the crater rim and peripheral ejecta has undergone relatively strong wind erosion and the eroded material was transport to the southwestern part of the impact crater,forming

关键词： Mars Elysium Planitia SHARAD Buried crater Permittivity inversion

SAR imaging simulation for an inhomogeneous undulated lunar surface based on triangulated irregular network

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Science in China(Series F) 2009年第4期52卷 559-574页

作者： fa wenzhe XU Feng JIN YaQiu Key Laboratory of Wave Scattering and Remote Sensing Information (MoE) Fudan University Shanghai 200433 China

Based on the statistics of the lunar cratered terrain, e.g., population, dimension and shape of craters, the terrain feature of cratered lunar surface is numerically generated. According to the inhomogeneous distribution of the lunar surface slope, the triangulated irregular network （TIN） is employed to make the digital elevation of lunar surface model. The Kirchhoff approximation of surface scattering is then applied to simulation of lunar surface scattering. The synthetic aperture radar （SAR） image for compre- hensive cratered lunar surface is numerically generated using back projection （BP） algorithm of SAR imaging. Making use of the digital elevation and Clementine UVVIS data at Apollo 15 landing site as the ground truth, an SAR image at Apollo 15 landing site is simulated. The image simulation is verified using real SAR image and echoes statistics.

关键词： cratered terrain triangulated irregular network SAR imaging back projection

Origin of pit chains in the floor of lunar Copernican craters

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Science China(Physics,Mechanics & Astronomy) 2010年第12期53卷 2145-2159页

作者： XIAO ZhiYong ZENG ZuoXun XIAO Long fa wenzhe HUANG Qian faculty of Earth Sciences China University of GeosciencesWuhan 430074China Research Center for Space Science and Technology China University of GeosciencesWuhan 430074China Institut de Physique du Globe de Paris 4 Avenue de NeptuneSaint Maur des Fosse’s94100France Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China

There are small pit chains in the floor of lunar Copernican craters. They are usually so small in scale that there are few lunar spacecrafts to detect their detailed morphology. Combining camera data from Lunar Orbiter, Lunar Reconnaissance Orbiter (LRO), Kaguya and Chang’e-1 missions, 5 representative large Copernican craters on various terrains of the lunar surface are chosen to study the origin of the pit chains in the crater floor. The morphology and distribution characteristic of the pit chains are referred by the high resolution images in this research. It is suggested that it is the magma activities from the subsurface magma layer combining with the existence of fractures and faults under the crater floor that leaded the formation of the pit chains. The model is further verified and discussed using the regolith thickness data in the crater floor. Our model suggests that the pit chains are still developing in the floor of the Copernican craters and the Moon may not be totally cold. Finally, the model limitation and potential future work are discussed based on available data.

关键词： lunar Copernican crater pit chains LRO LROC Kaguya Chang’e-1

Analysis of microwave brightness temperature of lunar surface and inversion of regolith layer thickness:Primary results of Chang-E 1 multi-channel radiometer observation

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Science China(Information Sciences) 2010年第1期53卷 168-181页

作者： fa wenzhe & JIN YaQiu Key Laboratory of Wave Scattering and Remote Sensing Information (MoE), Fudan University, Shanghai 200433, China Key Laboratory of Wave Scattering and Remote Sensing Information (MoE) Fudan University

In China’s first lunar exploration project, Chang-E 1 (CE-1), a multi-channel microwave radiometer was aboard the satellite, with the purpose of measuring microwave brightness temperature from lunar surface and surveying the global distribution of lunar regolith layer thickness. In this paper, the primary 621 tracks of swath data measured by Chang-E 1 microwave radiometer from November 2007 to February 2008 are collected and analyzed. Using nearest neighbor interpolation based on the sun incidence angle in observations, global distributions of microwave brightness temperature from lunar surface at lunar daytime and nighttime are constructed. Using the three-layer model (the top dust-soil, regolith and underlying rock media) for microwave thermal emission of lunar surface, the measurements of brightness temperature and dependence upon latitude, frequency and FeO+TiO2 content, etc. are discussed. On the basis of the ground measurements at Apollo landing sites, the observed brightness temperature at these locations are validated and calibrated by numerical three-layer modeling. Using the empirical dependence of physical temperature upon the latitude verified by the measurements at Apollo landing sites, the global distribution of regolith layer thickness is then inverted from the brightness temperature data of CE-1 at 3 GHz channel. Those inversions at Apollo landing sites are com- pared with the Apollo in situ measurements. Finally, the statistical property of regolith thickness distribution is analyzed and discussed.

关键词： Chang-E 1 multi-channel brightness temperature Apollo landing site physical temperature inversion of regolith layer thickness

月球表面物质介电常数:嫦娥五号月球样品的新启示

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中国科学：物理学、力学、天文学 2023年第3期53卷 2-26页

作者：法文哲北京大学地球与空间科学学院遥感与地理信息系统研究所北京100871

月表物质的介电常数决定了电磁波在月球次表层的穿透深度,对月球雷达、微波辐射计、月表电磁实验等科学载荷的设计与数据解译至关重要,有助于定量反演次表层结构与物理性质.对月球物质介电常数的了解,目前主要基于主被动微波遥感数据反... 详细信息

月表物质的介电常数决定了电磁波在月球次表层的穿透深度,对月球雷达、微波辐射计、月表电磁实验等科学载荷的设计与数据解译至关重要,有助于定量反演次表层结构与物理性质.对月球物质介电常数的了解,目前主要基于主被动微波遥感数据反演和对Apollo,Luna月球样品的实验测量.2020年12月,我国嫦娥五号探测器从月球正面风暴洋北部成功采集并返回1.731 kg月球样品,为研究月壤介电常数提供了新的样品.本文首先介绍了物质介电常数基础、介质电极化机制、介电常数混合模型和测量方法,接着对月球表面物质介电常数的研究历史与现状进行了系统性梳理与总结,并给出了整个月球表面月壤介电常数的分布图.最后,介绍了我国嫦娥五号着陆区地质背景与月壤特性的最新研究结果,对嫦娥五号月球样品介电常数实验测量给出了建议,并对其潜在科学产出进行了评估.本文对月壤介电常数的梳理与认识,可以为我国后续探月工程中微波遥感载荷设计、雷达数据解译、采样点选取和样品分析等提供理论指导与支撑.

关键词：月壤介电常数嫦娥五号

Preface: Joint researches are benefiting the Chang’E-1 comprehensive lunar scientific studies which probe ever deeper

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Science China(Physics,Mechanics & Astronomy) 2010年第12期53卷 2135-2135页

作者： ZhiYong Xiao ZuoXun Zeng Long Xiao wenzhe fa Qian Huang Special Topic Editor Shanghai Astronomical Observatory Chinese Academic of Sciences

PrefacePreface: Joint researches are benefiting the Chang’E-1 comprehensive lunar scientific studies which probe ever deeper

关键词： IIM VLBI E-1 comprehensive lunar scientific studies which probe ever deeper Joint researches are benefiting the Chang Preface